Rotary steerable tool
A rotary steerable tool has an inner mandrel having a longitudinal axis and an outer housing positioned along the inner mandrel. The outer housing rotates independently of the inner mandrel. The outer housing has an engagement member that moves axially relative to the outer housing and the inner mandrel between an extended position and a retracted position, and a transition surface having a slope relative to an outer surface of the outer housing. The engagement member moves along the transition surface between the extended position and the retracted position. In the engaged position, the engagement member extends outward from the outer housing to engage an inner surface of a well being drilled. An actuator selectively moves the engagement member along the transition surface from the retracted position to the extended position.
This relates to a rotary steerable tool that is designed for use in drilling applications to help steer the drilling string.
BACKGROUNDIn directional drilling, it is necessary to steer the drill bit in order to obtain the horizontal portion of the well, or to correct the drilling angle. When the drill bit is driven by a rotating body, this involves steering the tool in a constant direction despite the rotating tool.
SUMMARYAccording to an aspect, there is provided a rotary steerable tool, comprising an inner mandrel having a longitudinal axis and an outer housing positioned along the inner mandrel. The outer housing comprises an engagement member that moves axially relative to the outer housing between an extended position and a retracted position and a transition surface having a slope relative to an outer surface of the outer housing. The engagement member moves along the transition surface between the extended position and the retracted position. In the engaged position, the engagement member extends outward from the outer housing to engage an inner surface of a wellbore. The outer housing rotates independently of the inner mandrel when the engagement member is in the engaged position. There is an actuator that selectively moves the engagement member along the transition surface from the retracted position to the extended position.
According to another aspect, the engagement member may comprise a friction surface that engages the inner surface of the well being drilled in the extended position. The friction surface may be connected to an internal portion by a pivoting connection. The friction surface may comprise a plurality of sharp points.
According to another aspect, the actuator may comprise an electric or mechanical motor and a threaded rod, a hydraulic power source and a piston, or a hydraulically actuated ring.
According to another aspect, the outer housing may be a split case.
According to another aspect, the inner mandrel may be connected to a drill string.
According to another aspect, the drill string may comprise stabilizer members mounted at least one of above and below the outer housing.
According to another aspect, the outer housing may comprise a plurality of engagement members having a different height.
According to another aspect, the outer housing may comprise a pressure equalization valve.
According to another aspect, there is provided a drill string for directional drilling, comprising a rotary drill string body carrying a drill bit at a lower end of the rotary drill string body, and a rotary steerable tool spaced from the drill bit as described above.
According to another aspect, there is provided a method of directional drilling, comprising the steps of securing an outer housing on a drill string, the outer housing comprising an engagement member that moves axially relative to the outer housing between an extended position and a retracted position and a transition surface having a slope relative to an outer surface of the outer housing; actuating the engagement member to move along the transition surface from the retracted position to the extended position such that the engagement member extends outward from the outer housing and engages an inner surface of a wellbore, the engagement member inducing a bend in the drill string; and rotating the drill string independently of the outer housing when the engagement member is in the engaged position against the inner surface of the wellbore.
According to another aspect, the method may further comprise the step of applying downward pressure to the drill string, the downward pressure further inducing a bending force on the drill string.
According to another aspect, the engagement member may comprises a friction surface, the friction surface engaging the inner surface of the wellbore to prevent rotation of the outer housing as the drill string rotates. The friction surface may comprise a plurality of sharp points.
Other aspects will be apparent from the specification and drawings.
These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:
A rotary steerable tool will now be described with reference to
Referring to
Referring to
Outer housing 24 houses an engagement member 26 that moves axially relative to outer housing 24 and inner mandrel 14 between a retracted position as shown in
Referring to
There will now be described the various ways in which tool 10 may be actuated. Referring to
In the process of regular rotary drilling, tool 10 does not need to be engaged and can be permitted to spins together with drill string 12. When the need to correct the drilling angle arises, tool 10 is engaged to the position shown in
Due to the fact that the MWD tools are located much closer to the drilling bit, all the measurements and locations received at the rig floor are much more accurate and current. Engagement member 26 preferably has several sharp triangular edged points acting as a friction surface 32. When engaged, it presses against the side of wellbore 28, causing a slight deviation from the longitudinal axis of the drill string 12. When the weight on drill string 12 is applied, it causes friction surface 32 to dig into the side of wellbore 28 even more. As drill string 12 starts to rotate and drill, even more pressure is applied, causing friction surface 32 to scrape or create grooves in the side of wellbore 28, preventing outer housing 24 from rotating around inner mandrel 14, hence creating a greater deviation from the longitudinal axis and thereby accomplishing directional drilling.
Another embodiment is shown in
As power ring 44 moves it causes the engaging member to move out of housing 24 and engage wellbore 28. As depicted, power ring 44 pushes the non-rotational ring 46. The force is transferred through pivoting connection 52 to engagement member 26 until it presses up against the wall of wellbore 28. After this, the entire drilling column is moved down a small distance as friction surface 32, which is made up of hardened steel as depicted, digs into the side of wellbore 28. The engagement member 26 then slides into its working position. When the engagement member 26 slides into its working position, MWD sensor 36 sends a signal to the ground, indicating that directional rotary drilling may commence.
While drill string 12 is rotating, the outer housing 24 does not. This is due to engagement member 26 pressing up against the inside of wellbore 28. Engagement member 26, through bearings 34 then presses onto drill string 12. Because of stabilizers 18, the pressure generated will cause an axial depression in the wellbore and causes drill string 12 to bend and thereby create an angle at which the drill bit 16 enters the earth. When the weight of the drill string is increased, a further axial depression against the wellbore will be created.
During directional rotary drilling, engagement member 26 is pressed up against wellbore 28, causing the hardened steel points on friction surface 32 to dig in. This stops outer housing 24 from moving and holds the correct angle.
To change the angle or to stop directional rotary drilling, the operation of drill string 12 is ceased and it is raised up from the bottom of wellbore 12. Because engagement member 26 is pressed up against wellbore 12, the friction will cause it to slide down and back into its retracted position. It may be necessary to reverse the electric motor or hydraulic power source while this occurs.
In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.
The following claims are to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and what can be obviously substituted. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.
Claims
1. A rotary steerable tool comprising:
- an inner mandrel having a longitudinal axis;
- an outer housing positioned along the inner mandrel, and the outer housing comprising:
- a split case;
- an engagement member that moves axially relative to the split case between an extended position and a retracted position, and the engagement member comprising a friction surface that engages an inner surface of a wellbore being drilled in the extended position; and
- a transition surface having a slope relative to an outer surface of the split case, the engagement member moving along the transition surface between the extended position and the retracted position, in the engaged position, the engagement member extending outward from the outer housing to engage the inner surface of the wellbore, and the outer housing rotating independently of the inner mandrel when the engagement member is in the engaged position; and
- an actuator that selectively moves the engagement member along the transition surface from the retracted position to the extended position, the actuator being powered by a power source.
2. The rotary steerable tool of claim 1, wherein the friction surface is connected to an internal portion by a pivoting connection.
3. The rotary steerable tool of claim 1, wherein the friction surface comprises a plurality of sharp points.
4. The rotary steerable tool of claim 1, wherein the actuator comprises a threaded rod and the power source comprises an electric motor or a mechanical motor.
5. The rotary steerable tool of claim 1, wherein the actuator comprises a piston and the power source comprises a hydraulic power source.
6. The rotary steerable tool of claim 1, wherein the actuator comprises a hydraulically actuated ring.
7. The rotary steerable tool of claim 1, wherein the inner mandrel is connected to a drill string.
8. The rotary steerable tool of claim 7, wherein the drill string comprises stabilizer members mounted at least one of above and below the outer housing.
9. The rotary steerable tool of claim 1, wherein the outer housing comprises a plurality of engagement members having a different height.
10. The rotary steerable tool of claim 1, wherein the outer housing comprises a pressure equalization valve.
11. A drill string for directional drilling comprising:
- a rotary drill string body carrying a drill bit at a lower end of the rotary drill string body;
- a rotary steerable tool spaced from the drill bit, and the rotary steerable tool comprising:
- an inner mandrel having a longitudinal axis;
- an outer housing positioned along the inner mandrel, and the outer housing comprising:
- a spilt case;
- an engagement member that moves axially relative to the split case between an extended position and a retracted position, the engagement member comprising a friction surface that engages an inner surface a wellbore being drilled in the extended position; and
- a transition surface having a slope relative to an outer surface of the split case, the engagement member moving along the transition surface between the extended position and the retracted position, in the engaged position, the engagement member extending outward from the outer housing to engage the inner surface of the wellbore, and the outer housing rotating independently of the inner mandrel when the engagement member is in the engaged position;
- an actuator that selectively moves the engagement member along the transition surface from the retracted position to the extended position, the actuator being powered by a power source; and
- at least one set of stabilizers spaced along the rotary drill string body from the rotary steerable tool.
12. The rotary steerable tool of claim 11, wherein the friction surface is connected to an internal portion by a pivoting connection.
13. The rotary steerable tool of claim 11, wherein the friction surface comprises a plurality of sharp points.
14. The drill string of claim 11, wherein the actuator comprises a threaded rod and the power source comprises an electric motor or a mechanical motor.
15. The drill string of claim 11, wherein the actuator comprises a piston and the power source comprises a hydraulic power source.
16. The drill string of claim 11, wherein the actuator comprises a hydraulically actuated ring.
17. The drill string of claim 11, further comprising a set of stabilizers above and below the rotary steerable tool.
18. The drill string of claim 11, wherein the outer housing comprises a plurality of engagement members having a different height.
19. The drill string of claim 11, wherein the outer housing comprises a pressure equalization valve.
2179567 | November 1939 | Strength |
2819039 | January 1958 | Lindsay |
3370657 | February 1968 | Antle |
4394881 | July 26, 1983 | Shirley |
4947944 | August 14, 1990 | Coltman |
5201375 | April 13, 1993 | Base et al. |
5310012 | May 10, 1994 | Cendre |
5311953 | May 17, 1994 | Walker |
5318137 | June 7, 1994 | Johnson et al. |
5603386 | February 18, 1997 | Webster |
5836406 | November 17, 1998 | Schuh |
6213226 | April 10, 2001 | Eppink et al. |
6427783 | August 6, 2002 | Krueger |
6761232 | July 13, 2004 | Moody et al. |
6840336 | January 11, 2005 | Schaaf et al. |
6892830 | May 17, 2005 | Noe |
7306056 | December 11, 2007 | Ballantyne et al. |
7306058 | December 11, 2007 | Cargill et al. |
7373995 | May 20, 2008 | Hughes et al. |
7971662 | July 5, 2011 | Beuershausen |
8011452 | September 6, 2011 | Downton |
8087479 | January 3, 2012 | Kulkarni et al. |
8104548 | January 31, 2012 | Ma et al. |
20100089583 | April 15, 2010 | Xu et al. |
20110031023 | February 10, 2011 | Menezes et al. |
20120018219 | January 26, 2012 | Runia |
- Jonny Haugen and Baker Hughes, “Rotary Steerable System Replaces Slide Mode for Directional Drilling Applications”, Oil and Gas Journal, Mar. 2, 1998. URL: http://www.ogj.com/articles/print/volume-96/issue-9/in-this-issue/general-interest/rotary-steerablesystem-replaces-slide-mode-for-directional-drilling-applications.html.
- Sandro Poli and Franco Donati of Agip S.p. A. and Joachim Oppelt, Detlef Ragnitz and Baker Hughes of INTEQ GmbH, “Advanced Tools for Advanced Wells: Rotary Closed Loop Drilling System—Results of Prototype Field Testing”, One Petro, Society of Petroleum Engineers, vol. 13, No. 2, Jun. 1998 URL: http://www.onepetro.org/mslib/app/Preview.do?paperNumber=00036884&societyCode=SPE.
- International Search Report Corresponding to PCT/CA2012/050358 mailed Jul. 17, 2012.
- International Preliminary Report on Patentability Corresponding to PCT/CA2012/050358 mailed Dec. 2, 2013.
Type: Grant
Filed: May 30, 2012
Date of Patent: Jan 3, 2017
Patent Publication Number: 20140083777
Inventor: Alexandre Korchounov (Calgary)
Primary Examiner: Kenneth L Thompson
Application Number: 14/116,377
International Classification: E21B 7/06 (20060101); E21B 7/04 (20060101);